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    Subject[REVERT for 3.1-rc7] staging: zcache: revert "fix crash on high memory swap"
    Hi Greg --

    Please revert the following commit, hopefully before 3.1 is released.
    Although it fixes a crash in 32-bit systems with high memory,
    the fix apparently *causes* crashes on 64-bit systems. Not sure why
    my testing didn't catch it before but it has now been observed in
    the wild in 3.1-rc4 and I can reproduce it now fairly easily.
    3.1-rc3 works fine, 3.1-rc4 fails, and 3.1-rc3 plus only this
    commit fails. Let's revert it before 3.1 and Seth and Nitin and I
    will sort out a better fix later.

    Reported-by: Francis Moreau <>
    Reproduced-by: Dan Magenheimer <>


    commit c5f5c4db393837ebb2ae47bf061d70e498f48f8c
    Author: Seth Jennings <>
    Date: Wed Aug 10 12:56:49 2011 -0500

    staging: zcache: fix crash on high memory swap

    zcache_put_page() was modified to pass page_address(page) instead of the
    actual page structure. In combination with the function signature changes
    to tmem_put() and zcache_pampd_create(), zcache_pampd_create() tries to
    (re)derive the page structure from the virtual address. However, if the
    original page is a high memory page (or any unmapped page), this
    virt_to_page() fails because the page_address() in zcache_put_page()
    returned NULL.

    This patch changes zcache_put_page() and zcache_get_page() to pass
    the page structure instead of the page's virtual address, which
    may or may not exist.

    Signed-off-by: Seth Jennings <>
    Acked-by: Dan Magenheimer <>
    Signed-off-by: Greg Kroah-Hartman <>

    diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c
    index 855a5bb..a3f5162 100644
    --- a/drivers/staging/zcache/zcache-main.c
    +++ b/drivers/staging/zcache/zcache-main.c
    @@ -1158,7 +1158,7 @@ static void *zcache_pampd_create(char *data, size_t size, bool raw, int eph,
    size_t clen;
    int ret;
    unsigned long count;
    - struct page *page = virt_to_page(data);
    + struct page *page = (struct page *)(data);
    struct zcache_client *cli = pool->client;
    uint16_t client_id = get_client_id_from_client(cli);
    unsigned long zv_mean_zsize;
    @@ -1227,7 +1227,7 @@ static int zcache_pampd_get_data(char *data, size_t *bufsize, bool raw,
    int ret = 0;

    - zv_decompress(virt_to_page(data), pampd);
    + zv_decompress((struct page *)(data), pampd);
    return ret;

    @@ -1539,7 +1539,7 @@ static int zcache_put_page(int cli_id, int pool_id, struct tmem_oid *oidp,
    goto out;
    if (!zcache_freeze && zcache_do_preload(pool) == 0) {
    /* preload does preempt_disable on success */
    - ret = tmem_put(pool, oidp, index, page_address(page),
    + ret = tmem_put(pool, oidp, index, (char *)(page),
    PAGE_SIZE, 0, is_ephemeral(pool));
    if (ret < 0) {
    if (is_ephemeral(pool))
    @@ -1572,7 +1572,7 @@ static int zcache_get_page(int cli_id, int pool_id, struct tmem_oid *oidp,
    pool = zcache_get_pool_by_id(cli_id, pool_id);
    if (likely(pool != NULL)) {
    if (atomic_read(&pool->obj_count) > 0)
    - ret = tmem_get(pool, oidp, index, page_address(page),
    + ret = tmem_get(pool, oidp, index, (char *)(page),
    &size, 0, is_ephemeral(pool));

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      Last update: 2011-09-13 19:41    [W:0.030 / U:12.072 seconds]
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